Lenses and optical devices

Abstract

The objective of the present invention is to provide a lens and an optical system device with which optical characteristics of a light source and an optical element can be measured in a simple configuration.　A lens 1 has an optical axis, comprises an incident surface F and an emission surface B, and is formed such that the incident surface F and the emission surface B cause light entering the incident surface F at an illumination angle θ relative to the optical axis from a first position O to be emitted at an emission angle θ / m (m>1) relative to the optical axis from the emission surface B by means of refraction by the incident surface F and the emission surface B, and all of the apparent positions of the light emitted from the emission surface B begin at a second position P. In addition, an optical system device is formed of the lens 1 and a diffusion plate for diffusing the light emitted from the lens 1.

Description

[Technical field]

[0001] The present invention relates to a lens and an optical system device using the lens. [Background technology]

[0002] In recent years, light-emitting elements such as LEDs have come to be used as light sources. In addition, optical elements such as microlens arrays (MLAs) and diffractive optical elements (DOEs) have been developed to control the light from various light sources. It is necessary to evaluate the optical properties, such as the orientation, of such light-emitting elements and optical elements. One such evaluation method is, for example, to rotate a light source or an imaging unit with a goniometer and measure the luminous intensity at that angle using a sensor. In this case, the measurement itself is relatively easy, but since the measurement itself is performed in a spot, there is a problem that it takes a very long time to obtain one piece of light distribution data. Another problem is that the goniometer is very expensive (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2016-151438 DISCLOSURE OF THEINVENTION [Problem to be solved by the invention]

[0004] One possible method is to observe the orientation of light emitted from a light-emitting element or optical element by projecting it onto a visualization plate. In this case, one piece of orientation data can be measured in a short time, but there is a limit to the light distribution angle that can be projected onto the visualization plate, and light with a large light distribution angle cannot be measured.

[0005] SUMMARY OF THE PRESENT EMBODIMENTS An object of the present invention is to provide a lens and an optical system device that can measure the optical characteristics of a light source or an optical element with a simple configuration. [Means for solving the problem]

[0006] The lens of the present invention has an optical axis and is composed of an entrance surface and an exit surface, and the entrance surface and the exit surface are characterized in that light incident on the entrance surface from a first position at an irradiation angle θ with respect to the optical axis is emitted from the exit surface at an exit angle θ / m (m>1) with respect to the optical axis due to refraction at the entrance surface and the exit surface, and the apparent positions of the light emitted from the exit surface all start from a second position.

[0007] In this case, the incident surface is shaped to refract the light incident at the irradiation angle θ from the first position so that it is irradiated from the second position to the intersection of the direction of angle θ / m and the exit surface, and the exit surface is shaped to refract the light irradiated from the first position through the incident surface in the direction of the exit angle θ / m.

[0008] Furthermore, m can be any number greater than 1, and is preferably m ≥ 2. Specifically, if m = 2, the emission angle can be made half the incidence angle.

[0009] The optical system device of the present invention is characterized in that it comprises a lens that receives light incident from a first position at an illumination angle θ relative to an optical axis and emits it at an emission angle θ / m (m>1) relative to the optical axis, and is formed so that the apparent positions of the emitted light all start from a second position, and a diffuser plate that diffuses the light emitted from the lens.

[0010] In this case, a wavelength selection filter that transmits only light of a specific wavelength may be provided.

[0011] The imaging device may also include an image sensor that detects light from the diffusion plate.

[0012] The imaging device may also include an electronic shutter that adjusts the time during which light is incident on the imaging element.

[0013] The imaging device may further comprise a calculation means for calculating an orientation characteristic from information on the light detected by the imaging element.

[0014] The imaging device may further include a display device that displays the orientation characteristics of the light detected by the imaging element.

[0015] The optical system may further include an anti-reflection member disposed around the diffusing plate in parallel with the optical axis of the lens, the anti-reflection member absorbing the light incident from the diffusing plate.

[0016] The imaging device may also include a light source that irradiates light onto the first position.

[0017] The imaging device may also include an imaging lens for forming an image of the light from the light source and irradiating the image on the first position.

[0018] Also, a polarizing filter that transmits only light polarized in a specific direction may be provided.

[0019] The lens may be the lens of the present invention described above. Effect of the Invention

[0020] The lens of the present invention can set the light distribution angle of light from a light source or optical element to 1 / m (m>1). Therefore, the optical system device of the present invention using the lens can measure the optical characteristics of a light source or optical element with a simple configuration. [Brief description of the drawings]

[0021] [Figure 1] FIG. 1 is a diagram illustrating a lens of the present invention. [Diagram 2] 1A to 1C are diagrams illustrating a method for producing a lens of the present invention. [Diagram 3] 1A to 1C are diagrams illustrating a method for producing a lens of the present invention. [Figure 4] 1 is a schematic cross-sectional view showing an optical system device of the present invention. [Diagram 5] FIG. 11 is a schematic cross-sectional view showing another optical system device of the present invention. [Figure 6] FIG. 11 is a schematic cross-sectional view showing another optical system device of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] The following describes the lens 1 of the present invention. The lens 1 of the present invention has an optical axis and is mainly composed of an entrance surface F and an exit surface B, as shown in FIG.

[0023] The incident surface F and the exit surface B emit light incident on the incident surface F at an irradiation angle θ with respect to the optical axis from the first position O at an exit angle θ / m (m>1) with respect to the optical axis from the exit surface B due to refraction at the incident surface F and the exit surface B. Here, m can be 2 or more, and can also be 3 or more. Specifically, if m=2, the exit angle can be half the incident angle. In addition, the incident surface F and the exit surface B are formed so that the apparent positions of the light emitted from the exit surface B all start from the second position P. Here, the apparent position (second position P) means the position of the point where the light ray emitted from the exit surface B intersects with the optical axis when it is extended in the optical axis direction.

[0024] More specifically, the entrance surface F is shaped to refract light incident from a first position O at an irradiation angle θ so that it is irradiated from a second position P at an angle θ / m toward the intersection of the exit surface B.

[0025] Moreover, the exit surface B has a shape that refracts the light irradiated from the first position O through the entrance surface F in the direction of an exit angle θ / m.

[0026] The entrance surface F and the exit surface B may be formed in any manner, but for example, they are formed as follows. (1) As shown in FIG. 2, an arbitrary first position O (origin) and an optical axis (x-axis) passing through the first position O are determined. (2) In the xy plane (the plane of the paper in Figure 2) including the optical axis, a point F0 (f, 0) representing the entrance surface F and a point B0 (b, 0) representing the exit surface B are determined at arbitrary positions on the optical axis. (3) A second position P(-p, 0) is determined on the optical axis on the opposite side of the entrance surface F with respect to the first position O. (4) Define small angles δα and δβ such that δβ = δα / m (m>1). (5) The points representing the incident surface F are arranged in order from the optical axis side to F 0、 F 1、 F2...F n (n is a natural number), and the points representing the exit surface B are arranged in order from the optical axis side to 0、 B 1、 B2···B n (n is a natural number). (6) Define F1=(f,ftan(δα)), B1=((b+l),(b+l)tan(δβ)). (7) With the vectors OF1, F1B1, and LB1 determined, according to Snell's law, the inclination Φ of the plane of incidence F with respect to the x-axis when the ray OF1 is refracted to become the ray F1B1 is F1、 The inclination Φ of the exit surface B where the light ray F1B1 is refracted to become the light ray LB1 with respect to the x-axis B1 is decided. Passing through point F1, with a slope of Φ f The intersection of the line with the slope 2δα passing through point O and the line with the slope 2δα is F2. Also, it passes through point B1 and has a slope of Φ b The intersection of the line with the slope 2δβ that passes through point L and the line with the slope 2δβ is B2. (8) By similar calculation, vector OF n-1 , F n-1 B n-1 , L.B. n-1 is determined, and according to Snell's law, the ray OF n-1 is refracted into ray F n-1 B n-1 The inclination Φ of the incident surface F with respect to the x-axis F(n-1)、 Ray F n-1 B n-1 is refracted into ray LB n-1 The inclination of the exit surface B with respect to the x-axis is Φ B(n-1) is decided. point F n-1 Passing through, with a slope of Φ F(n-1) The intersection point of the line with the slope nδα and the line with the slope nδα through point O is F. n It becomes. Also, point Bn-1 Passing through, with a slope of Φ B(n-1) The intersection point of the line with the slope nδβ passing through point L is B. n It becomes. (9) Point F calculated in this way 0、 F 1、 F2...F n (n is a natural number), B 0、 B 1、 B2···B n (n is a natural number), the entrance surface F and the exit surface B on the xy plane can be formed (see Figure 3). n and point B n During this time, ray F n B n Any shape may be used as long as it does not interfere with the above. (10) The plane shape thus formed can be rotated about the optical axis to form the entrance surface F and the exit surface B of the lens 1 of the present invention.

[0027] Lens 1 of the present invention may have a portion that does not interfere with entrance surface F and exit surface B, such as a support portion for supporting lens 1 on a side surface.

[0028] The optical system device of the present invention is for measuring the optical characteristics of a measurement object 100, as shown in FIG.

[0029] Here, the measurement object 100 refers to a light-emitting element such as an LED that emits light by itself, or an optical element that controls and emits incident light such as a microlens array (MLA) or a diffractive optical element (DOE). Of course, the measurement object 100 is not limited to these as long as it can emit incident light.

[0030] The lens 1 is formed so that the light incident from the first position O at an irradiation angle θ with respect to the optical axis is emitted at an emission angle θ / m (m>1) with respect to the optical axis, and the apparent positions of the emitted light all start from the second position P. That is, the light distribution angle of the light from the light source 6 or the optical element can be set to 1 / m (m>1). Here, m can be 2 or more, and can also be 3 or more. This can reduce the incident angle of the light irradiated to the diffusion plate 2, and the size of the diffusion plate 2 can be reduced. For example, if m=2, the emission angle can be half the incident angle. The lens 1 of the present invention described above can be used as the lens.

[0031] The diffusion plate 2 diffuses the light emitted from the lens 1. This makes it possible to convert the three-dimensional orientation of the light emitted from the lens 1 into a two-dimensional image.

[0032] The optical system device of the present invention may also include a wavelength selection filter 3. The wavelength selection filter 3 is an optical element that transmits only light of a specific wavelength and does not transmit light of other wavelengths. When the wavelength of light to be detected from the measurement object is known, the wavelength selection filter 3 that transmits only the light can be used to cut out other light that becomes noise and perform measurement. The wavelength selection filter 3 may be disposed between the measurement object 100 and the image sensor 4, preferably between the diffusion plate 2 and the image sensor 4, and more preferably immediately before the image sensor 4, so that light other than the light of the specific wavelength is not incident on the image sensor 4. Examples of the wavelength selection filter 3 include a band pass filter, a long pass filter, a short pass filter, and a color filter.

[0033] In order to capture the optical characteristics as data rather than visually, the optical system device of the present invention may include other devices such as an image sensor 4 and a computing means, as shown in FIG.

[0034] The imaging element 4 detects light from the diffusion plate 2. As the imaging element 4, an element that converts an image into an electric signal, for example, a solid-state imaging element 4 such as a CCD image sensor or a CMOS image sensor, can be used. Also, the imaging element 4 can be one that is sensitive not only to visible light, but also to infrared light, ultraviolet light, or X-rays. The imaging element 4 may also be provided with a separate electronic shutter or the like that adjusts the time that light is incident on the imaging element 4.

[0035] The calculation means calculates the orientation characteristics from the information of the light detected by the imaging element 4. For example, the light detected by the imaging element 4 differs from the orientation characteristics of the object to be actually measured due to errors caused by distortion of the lens 1, errors caused by the angle of the light incident on the diffusion plate 2 and the in-plane uniformity of the diffusion plate 2, differences in light intensity between the diffusion plate 2 and the far field, etc. The calculation means can also calculate the actual orientation characteristics from the information of the light detected by the imaging element 4 by correcting the above errors, etc.

[0036] When correcting the distortion of the lens 1, for example, a chessboard with known dimensions is placed at different positions within the screen of the image sensor 4, and each image is acquired. Next, the coordinates of the lattice points are extracted from the images, and correction parameters are calculated from the correspondence between the real space coordinates and the camera coordinates. The calculation means corrects the distortion of the lens 1 based on the information on the light detected by the image sensor 4 and the correction parameters, and calculates the actual orientation characteristics.

[0037] Furthermore, when correcting errors due to the angle of light incident on the diffuser 2 or the in-plane uniformity of the diffuser 2, for example, a laser pointer is used to directly irradiate light onto the diffuser from the second position P, and image data is acquired by the image sensor 4 while varying the position (x, y) of the light irradiated onto the diffuser 2. Next, a correction coefficient K(x, y) expressed by the following formula is calculated based on the luminance of the light from the laser pointer. K(x,y) = Light brightness at position (x,y) / Laser pointer light brightness The calculation means may correct errors due to the angle of light incident on the diffusion plate 2 and the in-plane uniformity of the diffusion plate 2 based on the information of the light detected by the imaging element 4 and the above-mentioned correction coefficient K(x, y).

[0038] The difference in light intensity between the diffuser 2 and the far field is expressed as follows: D is the distance between the apparent light source and the diffuser 2, r is the distance from the optical axis on the diffuser 2, θ is the angle of incidence of light from the light source to the optical axis on the lens 1, θ / m is the angle of incidence of light from the lens 1 to the diffuser 2, and I is the light intensity on the diffuser 2. r (r) The light intensity in the far field when passing through lens 1 is I' θ (θ / m), the following equation holds: JPEG0007641023000001.jpg20103Also, let I be the light intensity in the far field when it does not pass through lens 1. θ If (θ), then Since the image is JPEG0007641023000002.jpg2282, the following formula holds: JPEG0007641023000003.jpg2195 Therefore, the calculation means may correct the difference in light intensity between the diffuser plate 2 and the far field based on the information on the light detected by the image sensor 4 and the above formula.

[0039] The display means displays the orientation characteristics of the light detected by the imaging element 4. This makes it possible to easily check the orientation characteristics of the measurement target object 100. As the display means, a conventional display can be used.

[0040] Furthermore, of the light diffused by the diffuser 2, the remaining light, excluding the light directly incident on the imaging element 4, becomes noise when it is reflected or otherwise incident on the imaging element 4. Therefore, it is preferable that the optical system device of the present invention has an anti-reflection member 5 that is disposed around the diffuser 2 in parallel with the optical axis of the lens 1 and absorbs the light incident from the diffuser 2. If the anti-reflection member 5 absorbs the light incident from the diffuser 2, the light can be prevented from being reflected and incident on the imaging element 4.

[0041] Also, if the measurement object 100 is an object that emits light by itself, such as a light-emitting element, a light source 6 is not necessary, but if the measurement object 100 is an optical element such as a microlens array (MLA) or a diffractive optical element (DOE), a light source 6 is necessary to irradiate the measurement object 100 with light, as shown in Fig. 5. The light source 6 may be any light source that can irradiate the measurement object 100 placed at the first position O with light, and for example, a vertical-cavity surface-emitting laser (VCSEL) can be used. The distance between the light source 6 and the first position O is arbitrary as long as it can irradiate light to the measurement range of the measurement object 100.

[0042] In addition, it is desirable to inspect all measurement objects such as microlens arrays during mass production. In this case, the position of the measurement object 100 relative to the light source 6 is controlled by an actuator or the like, but if the distance between the light source 6 and the measurement object 100 is short, there is a high possibility of contact. Therefore, the optical system device of the present invention may have an imaging lens 7 for forming an image of the light from the light source 6 and irradiating the first position O, as shown in FIG. 6. If the light from the light source 6 is irradiated to the first position O through the imaging lens 7, the distance between the light source 6 and the measurement object 100 can be increased. Note that the distance between the imaging position and the first position O is arbitrary as long as the light can be irradiated to the measurement range of the measurement object 100.

[0043] A polarizing filter is an optical element that transmits only light polarized in a specific direction. When the measurement object is an object that polarizes light in a specific direction, such as a polarizer or a phase difference element, the polarizing filter can be used to measure only light polarized in a specific direction. The polarizing filter may have a rotation means for rotating the polarizing filter. The polarizing filter may be disposed between the measurement object 100 and the image sensor 4, preferably between the diffusion plate 2 and the image sensor 4, and more preferably immediately before the image sensor 4, so that light other than light polarized in a specific direction is not incident on the image sensor 4. [Explanation of symbols]

[0044] F entrance plane B Output surface O 1st position P 2nd position 1 Lens 2 Diffuser 3 Wavelength selection filter 4. Image sensor 5. Anti-reflective materials 6 light source 7 Imaging Lens 100 Measurement object

Claims

1. a lens that emits light incident from a first position at an irradiation angle θ with respect to an optical axis at an emission angle θ / m (m>1) with respect to the optical axis, and is formed so that the apparent positions of the emitted light all start from a second position; A diffusion plate that diffuses the light emitted from the lens; an image sensor that detects light from the diffusion plate; An optical system device comprising:

2. 2. The optical system according to claim 1, further comprising a wavelength selection filter that transmits only light of a specific wavelength.

3. 3. An optical system according to claim 1, further comprising an electronic shutter for adjusting a time during which light is incident on said image sensor.

4. 4. The optical system according to claim 1, further comprising a calculation means for calculating an orientation characteristic from information on the light detected by the image pickup element.

5. 5. The optical system according to claim 1, further comprising a display device for displaying the light orientation characteristic detected by the image sensor.

6. 6. The optical system device according to claim 1, further comprising an anti-reflection member disposed around the diffusing plate in parallel with the optical axis of the lens, for absorbing the light incident from the diffusing plate.

7. 7. The optical system according to claim 1, further comprising a light source for irradiating the first position with light.

8. 8. The optical system according to claim 7, further comprising an imaging lens for forming an image of the light from the light source and irradiating the image on the first position.

9. 9. The optical system according to claim 1, further comprising a polarizing filter that transmits only light polarized in a specific direction.

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